Three six-year-old boys ran a sex club at a Brisbane, Australia, state school demanding and receiving sexual favors from classmates, a father has claimed.

The outraged father alleged Friday the school did not bother to tell him for more than a week that his son was involved.

He spoke out as similar stories emerged at state schools on the Gold and Sunshine coasts and in Cairns, which indicate the sexual abuse of young students by other school children appears rampant.

The Brisbane father said his son was one of a trio seen performing various sex acts in a bathroom.

"The teachers interrogated the kids and made them write out statements without our consent," he said. "The boys wrote down that they belonged to a sex club.

"The teachers didn't make contact for six days. They sent me an email and said, 'Sorry, we've been busy'. We believe older children were also involved."

The father has demanded a full police investigation.

His revelations came as uproar was sparked by a story that told how the sexual assault of a seven-year-old girl by a young classmate was dismissed as a "childhood experiment" by a country school principal.

On the Sunshine Coast, a gang of nine-year-old boys has been accused of "grooming" children as young as five to engage in sex acts. Investigators were told victims were rewarded with candy.

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